Not Applicable
The present invention relates to a golf ball. More specifically, the present invention relates to a dimple pattern for a golf ball in which the dimple pattern has different sizes of dimples.
Golfers realized perhaps as early as the 1800""s that golf balls with indented surfaces flew better than those with smooth surfaces. Hand-hammered gutta-percha golf balls could be purchased at least by the 1860""s, and golf balls with brambles (bumps rather than dents) were in style from the late 1800""s to 1908. In 1908, an Englishman, William Taylor, received a patent for a golf ball with indentations (dimples) that flew better and more accurately than golf balls with brambles. A.G. Spalding and Bros., purchased the U.S. rights to the patent and introduced the GLORY ball featuring the TAYLOR dimples. Until the 1970s, the GLORY ball, and most other golf balls with dimples had 336 dimples of the same size using the same pattern, the ATTI pattern. The ATTI pattern was an octahedron pattern, split into eight concentric straight line rows, which was named after the main producer of molds for golf balls.
The only innovation related to the surface of a golf ball during this sixty year period came from Albert Penfold who invented a mesh-pattern golf ball for Dunlop. This pattern was invented in 1912 and was accepted until the 1930""s.
In the 1970""s, dimple pattern innovations appeared from the major golf ball manufacturers. In 1973, Titleist introduced an icosahedron pattern which divides the golf ball into twenty triangular regions. An icosahedron pattern was disclosed in British Patent Number 377,354 to John Vernon Pugh, however, this pattern had dimples lying on the equator of the golf ball which is typically the parting line of the mold for the golf ball. Nevertheless, the icosahedron pattern has become the dominant pattern on golf balls today.
In the late 1970s and the 1980""s the mathematicians of the major golf ball manufacturers focused their intention on increasing the dimpled surface area (the area covered by dimples) of a golf ball. The dimpled surface for the ATTI pattern golf balls was approximately 50%. In the 19703 s, the dimpled surface area increased to greater than 60% of the surface of a golf ball. Further breakthroughs increased the dimpled surface area to over 70%. U.S. Pat. No. 4,949,976 to William Gobush discloses a golf ball with 78% dimple coverage with up to 422 dimples. The 1990""s have seen the dimple surface area break into the 80% coverage.
The number of different dimples on a golf ball surface has also increased with the surface area coverage. The ATTI pattern disclosed a dimple pattern with only one size of dimple. The number of different types of dimples increased, with three different types of dimples becoming the preferred number of different types of dimples. U.S. Pat. No. 4,813,677 to Oka et al., discloses a dimple pattern with four different types of dimples on the surface where the non-dimpled surface cannot contain an additional dimple. United Kingdom patent application number 2157959, to Steven Aoyama, discloses dimples with five different diameters. Further, William Gobush invented a cub octahedron pattern that has dimples with eleven different diameters. See 500 Year of Golf Balls, Antique Trade Books, page 189. However, inventing dimple patterns with multiple dimples for a golf ball only has value if such a golf ball is commercialized and available for the typical golfer to play.
Additionally, dimple patterns have been based on the sectional shapes, such as octahedron, dodecahedron and icosahedron patterns. U.S. Pat. No. 5,201,522 discloses a golf ball dimple pattern having pentagonal formations with an equal number of dimples thereon. U.S. Pat. No. 4,880,241 discloses a golf ball dimple pattern having a modified icosahedron pattern wherein small triangular sections lie along the equator to provide a dimple-free equator. Although there are hundreds of published patents related to golf ball dimple patterns, there still remains a need to improve upon current dimple patterns. This need is driven by new materials used to manufacture golf balls, and the ever increasing innovations in golf clubs.
The present invention provides a novel dimple pattern that reduces high speed drag on a golf ball while increasing its low speed lift thereby providing a golf ball that travels greater distances. The present invention is able to accomplish this by providing multiples sets of dimples arranged in a pattern that covers at least eighty-five percent of the surface of the golf ball. One aspect of the present invention is a dimple pattern on a golf ball in which the dimple pattern has at least eighteen different sets of dimples. Each of the eighteen different sets of dimples has a different entry radius than any other set of dimples. The dimples cover at least 85% of the surface of the golf ball. Another aspect of the present invention is a golf ball having at least 382 dimples. The 382 dimples are partitioned into at least eleven different sets of dimples. Each of the eleven different sets of dimples has a different diameter than any other set of dimples. The 382 dimples cover at least 85% of the surface of the golf ball. Yet another aspect of the present invention is a golf ball having a core, an intermediate layer and cover. The core is composed of a polybutadiene material. The intermediate layer is composed of a ionomer blend and has a thickness ranging from 0.04 inch to 0.08 inch. The cover is composed of a thermosetting polyurethane, and has a thickness ranging from 0.02 inch to 0.05 inch. The cover has eighteen different sets of dimples. The golf ball has an average lift coefficient ranging from 0.24 to 0.26, and an average drag coefficient ranging from 0.230 to 0.226. The average lift coefficient is the average of four lift coefficient values consisting of the lift coefficient of the golf ball at a Reynolds number of 70,000 and 2000 rpm, the lift coefficient of the golf ball at a Reynolds number of 70,000 and 3000 rpm, the lift coefficient of the golf ball at a Reynolds number of 80,000 and 2000 rpm, and the lift coefficient of the golf ball at a Reynolds number of 80,000 and 3000 rpm. The average drag coefficient is the average of six drag coefficient values consisting of the drag coefficient of the golf ball at a Reynolds number of 120,000 and 2000 rpm, the drag coefficient of the golf ball at a Reynolds number of 120,000 and 3000 rpm, the drag coefficient of the golf ball at a Reynolds number of 150,000 and 2000 rpm, the drag coefficient of the golf ball at a Reynolds number of 150,000 and 3000 rpm, the drag coefficient of the golf ball at a Reynolds number of 180,000 and 2000 rpm, and the drag coefficient of the golf ball at a Reynolds number of 180,000 and 3000 rpm. Having briefly described the present invention, the above and further objects, features and advantages thereof will be recognized by those skilled in the pertinent art from the following detailed description of the invention when taken in conjunction with the accompanying drawings.